Insomniac (noun)

A person suffering from insomnia, especially a chronic inability to obtain sufficient sleep.

Origin:

Early 17th century: from latin insomniac- "sleepless", from the verb insomniare, from in- "not" + somniare "to sleep".

Examples:

1. She became an insomniac after the death of her husband.
2. He was an insomniac and often stayed up late into the night.
3. The insomniac struggled to fall asleep each night.
4. The insomniac relied on sleeping pills to get through the night.
5. The insomniac was often tired and irritable due to lack of sleep.